Analysis of interstitial concentrations of ATP from rat soleus muscle using microdialysis combined with ion-pairing high performance liquid chromatography (HPLC)

In the present study, a method is described for the determination of ATP in small samples of interstitial fluid (< 100 mul) using microdialysis combined with ion-pairing high performance liquid chromatography (HPLC) in a gradient elution system which gives a clear separation of ATP from other interstitial constituents. Lactic acid infusion was performed to stimulate ATP to exit the cells to appear in the interstitial space. Microdialysis probe is used to in-vivo sample the molecules in the interstitial fluid. Interstitial ATP could be reliably detected at concentrations higher than 1times10^-9 M. The present study provides a simple, sensitive and selective assay for endogenous extracellular concentrations of ATP from rat soleus muscle.